Kate Johnson

September 11, 2014

WASHINGTON, DC — Relaxed restrictions on experimental Ebola interventions, recently announced by the World Health Organization (WHO), are welcome news, according to one of the pioneers of the experimental Ebola drug Zmapp (Mapp Biopharmaceutical Inc).

West Africa is an Ebola "war zone," where outbreak response should be the primary focus, Gary Kobinger, PhD, chief of special pathogens at the Public Health Agency of Canada, said in a presentation here at the 54th Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC).

Fear, sparked by the high death rate at most treatment centers, has kept many contagious patients at home and spreading the virus in their communities, explained Dr. Kobinger.

"If we could just have options, people would go to the treatment centers instead of hiding, and these chains of transmission would stop," he told Medscape Medical News.

Zmapp is able to reverse Ebola disease in nonhuman primates up to day 5 Dr. Gary Kobinger

Dr. Kobinger and his team from the National Microbiology Lab in Winnipeg, Manitoba, Canada, were recently in the headlines following publication of their study demonstrating ZMapp's dramatic cure rates in monkeys infected with Ebola.

"Zmapp is able to reverse Ebola disease in nonhuman primates up to day 5 [of infection]," Dr. Kobinger told delegates at ICAAC, explaining that previous work in his lab had shown treatment response only up to 24 hours.

To see protection at day 5 "seemed almost impossible to us," he said. "This is very encouraging, compared to other products."

Calling Zmapp "the best option of the experimental therapeutics currently in development," Dr. Kobinger and his fellow researchers are urging speedy safety testing of the drug in humans, "preferably within the next few months, to enable the compassionate use of Zmapp as soon as possible."

Scaling Up Production

Supplies of ZMapp, which had been intended for research use only, are currently depleted. According to the WHO, "efforts to scale up production may yield increased supplies of potentially a few hundred doses by the end of 2014."

While emphasizing the priority of outbreak response in the field, Dr. Kobinger also underscored the importance of continued research.

The experimental VSV-EBOV vaccine (NewLink Genetics Corp) and another experimental vaccine using a chimpanzee adenovirus (GlaxoSmithKline) are both considered promising by the WHO and have been cleared to begin clinical trials.

Research just published by Dr. Kobinger's group shows the VSV-EBOV vaccine, predicted by the WHO to hit the ground first, can induce sustained long-term response against Ebola in rodents.

Dr. Kobinger was unable to give an exact timeline for the start of trials for the vaccine but said that it will be within a few weeks.

According to the Centers for Disease Control and Prevention, testing on the GSK vaccine was to begin this week at the National Institutes of Health Clinical Center in Bethesda, Maryland.

The WHO has said that clinical trial results for both vaccines may be available this November.

Exploring All Options

Moving both vaccines forward is very important, said Dr. Kobinger. "Maybe one will be better, or both will be good and offer more options. It's very encouraging to see that a lot of people got together to make this happen so quickly. If phase 1 data become available while this outbreak is still ongoing, it will be an opportunity for these vaccines to play a part, at least for healthcare workers."

Any therapeutic options, experimental or otherwise, that can be offered to healthcare workers could have "tremendous impact on the outbreak" he said. "Currently it's hard to convince healthcare workers to go or return to treatment centers."

Dr. Kobinger also applauded the WHO's decision last week to allow the use of convalescent plasma in the field, although he acknowledged that it has no proven efficacy in Ebola; it has not been shown to work in nonhuman primates, and its efficacy was hard to measure in 7 humans who tried it during a 1995 outbreak.

Still, there's "big hope" for convalescent plasma, says Dr. Kobinger.

"I think it's important because it's a very easy access therapy," he said. "This is a proven approach, though not in Ebola. There is a desire to do anything, to do something."

But while patient care is of utmost importance, many researchers believe strongly that research should not suffer.

"We must also consider observational and experimental research as a core component of an outbreak response," Robert Fowler, MD, from the University of Toronto, Ontario, Canada, and his colleagues wrote recently in the American Journal of Respiratory and Critical Care Medicine.

"While improving the care of infected patients takes precedence, we must concurrently improve our research response," they point out. "If we attempt to initiate clinical research only during the outbreak, it rarely occurs."

They note, "We need to fundamentally change the model of clinical research development and funding for outbreaks and pandemics from reaction to research-ready preparedness."

Dr. Kobinger and Dr. Fowler have disclosed no relevant financial relationships.

54th Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC). Presented September 8, 2014.


Comments on Medscape are moderated and should be professional in tone and on topic. You must declare any conflicts of interest related to your comments and responses. Please see our Commenting Guide for further information. We reserve the right to remove posts at our sole discretion.